Towards better circular economy and life cycle assessment through systems thinking and examining the interrelationships among sustainability, food systems and diet

Abstract

This thesis focuses on the theoretical and philosophical basis and robustness of existing methods of circular economy, life cycle assessment and other related methods focusing on issues of sustainability, food systems and diet. The purpose of this thesis is to identify weaknesses and strengths of current methods related to sustainability and food systems, and provide possible directions for improving current methods and practices.Current circular economy and LCA studies of the interrelationships among environmental sustainability, food systems and diet very often have limitations, including narrowly defined boundaries of the food systems, insufficient sustainability indicators, and limitation of databases and so on. These problems indicate that the current circular economy and LCA studies to some degree deviate from the initial need of more systemic or holistic approaches and views (Wikstrom et al. 2014; Frischknecht et al. 2016; Peters et al. 2010).To better understand those problems and to find solutions, this study conducted a systematic review on studies of LCA and circular economy on the topic of food system and diet sustainability, and conducted meta-analysis of relevant research methods and models focusing on the interrelationships among environmental sustainability, food systems and diet. By doing this, the study critically evaluated the use of circular economy principles and related concepts of a biophysically based economy, and contributed to methodological and theory developments in transdisciplinary integrated research for understanding the interrelationships. The thesis examined and interpreted a set of existing quantitative and conceptual methods related to circular economy focusing on the interrelationships among sustainability, food systems and human diet, in order to investigate: first, the theoretical and philosophical basis for links between economic and biophysical components in the common integrative tools and models used in sustainability decision-making of food systems; second, the robustness of present-day methods or models for analyses involving environmental impacts, resource demands, and economic measures. The thesis investigated what common sustainability models were based on, mainly in terms of epistemology, what they were intended for, and how they could possibly be combined or coupled methodologically in the future. This required using concepts and methods from systems thinking and analysis, scientific understanding of processes of social-ecological system change, and also the philosophy of science.This study found that there was a major emphasis on using GHG emissions and sometimes GHG emissions as the only indicator in LCAs to measure environmental sustainability, and little attention has been paid to look at the issue from the angles of health and food systems. The incomplete inclusion of food life cycle phases and selection of sustainability indicators for assessment in studies of LCAs and circular economy had their apparent advantages and limitations. To mitigate the limitations, this study suggested researchers find a balance between quantification and wholeness when using LCA to evaluate food system sustainability. For stronger food circular economy, this research recommended integrating the attributes of temporality, seasonality, regionality and complexity of food into the contexts of circular economy and circular bioeconomy. Also, focusing on management strategies to enable better circularity to optimise food systems rather than a single food product or waste, and on improving cross-chain valorisation of food wastes rather than valorisation of a single type of wastes also proved to be useful for that purpose. This study strongly suggested using systems thinking, stronger boundary critique, inclusion of broader phases and sustainability indicators, focusing more on the sustainability impacts of activities at the consumer end of the food life cycle, and further developing selection criteria for indicators to improve the current method of LCAs and circular economy.The outcomes of this thesis are expected to feed into future system analysis and modelling of interrelationships among environmental sustainability, food systems and human diet and health.